Memory rehabilitation post-stroke
ing (6). Findings are discrepant from previous CCT
studies in which improvement in objective memory
has been described (34–36). Possible explanations for
inconsistency in findings may relate to discrepancies in
training platforms, samples and design of these studies.
Most previous CCT studies have used CogMed QM
training, which selectively targets WM. In addition,
previous studies have commonly used mixed aetio-
logy samples (35, 36), which limits generalization to
stroke. Moreover, the most widely cited stroke CCT
study (34) failed to incorporate follow-up assessment,
an active control or blinded assessors. Limitations are
particularly pertinent given the vulnerability of CCT
to placebo effects (6) and may account for disparate
findings. Given that Lumosity TM is arguably the most
popular and widely recognized CCT programme
currently available (30) and purports to remediate
everyday memory, its effectiveness requires ongoing
empirical validation.
There were short-term effects of MSG intervention
on subjective ratings of everyday and memory failures
and CCT close other ratings of PM difficulties, though
these were not seen at follow-up. Within this context,
it is possible that the inclusion of “booster sessions” to
consolidate treatment gains may be necessary to main-
tain the benefits of the MSG intervention over time; a
finding previously described in brain-injured samples
(37). Regarding self-reported strategy use, while all
participants reported a significant increase in strategy
use over time, improvement was only maintained for
participants allocated to the MSG. This interaction
was not seen for external strategy use. These findings
suggest that MSG, but not CCT, may be effective in
improving the frequency of internal strategy use; a
finding supported by recent qualitative analysis (38).
Group discrepancies in strategy use may relate to the
context in which this information is acquired. While
participants in the MSG were taught strategies in a
structured group format and actively encouraged to
apply them to everyday tasks, participants in the CCT
intervention appeared to spontaneously implement
internal strategies to improve their task performance.
This adoption of strategies in CCT has been previously
described, and has been suggested as contributing to
the transfer of computerized interventions to untrained
activities (39). Nevertheless, the likely variable manner
in which participants implemented these strategies to
everyday tasks may account for their lack of sustained
effectiveness and everyday applicability. Findings are
consistent with qualitative feedback from CCT parti-
cipants who considered strategy use as “cheating” and
failed to see the generalization to real-world strategy
use (38). Future research should seek to explore the
efficacy of combined CCT with compensatory memory
349
strategy training to encourage generalization of spon-
taneously implemented strategy use.
Some methodological limitations of this study
are acknowledged. Importantly, the study compared
group, centre-based training of compensatory strate-
gies with individual, home-based computer training.
Consequently, we were unable to control for the ef-
fects of group socialization not present in CCT. Thus,
we cannot rule out the possibility that some of the
improvement evident in MSG participants may have
resulted from group participation, rather than group
content per se. However, this was a deliberate deci-
sion on behalf of researchers to maintain ecological
validity through delivery of the interventions as they
are clinically intended, to facilitate the translation of
findings. Similarly, although the MSG is a manualized
intervention, participants allocated to this condition
may have had the opportunity to raise specific goals,
not seen in CCT participants. Future research should
seek to explore the impact of group delivered CCT to
assist in delineating the influence of content vs medium
of delivery.
The subjective nature of several outcome measures
may be prone to measurement error. Regular interac-
tion with researchers for intervention, but not WC
participants may also have led to Hawthorne effects,
particularly given the subjective nature of outcomes
(40). However, these effects do not explain differences
between MSG and CCT groups, which remains the
aim of this paper. Similarly, participants in the study
often had difficulty specifying memory goals, parti-
cularly given their abstract nature. Notwithstanding,
participants appeared to understand the process of
goal setting, and potential difficulties were controlled
for across groups. Interestingly, the majority of WC
participants described achieving a memory goal in the
absence of a structured intervention. Results highlight
the potential therapeutic effect of goal setting but also
support the added benefit of MSG training beyond
these benefits. Findings further demonstrate the need
for a control condition to robustly explore the impact
of health interventions.
In addition, eligibility was not limited to individuals
with objective memory impairment, which may explain
the relatively mild nature of memory impairment in this
sample. The inclusion criterion of subjective memory
complaints was selected deliberately to reflect the
patient population that is most likely to present for me-
mory rehabilitation services. Access to memory rehabi-
litation services is not usually contingent on objective
memory impairment from a clinical perspective. Our
primary aim was to understand if these interventions
improved everyday memory function irrespective of
the underlying cause of change. Nonetheless, findings
J Rehabil Med 51, 2019